Sand Sorter Update April 2011

1. Sand Sorter Update April 2011 Comments or questions: Post to BSF-Production Group: bsf-production@googlegroups.com Or contact: Derek Baker (dbaker@cawst.org) or Olivier Mills (omills@cawst.org) For previous updates go to: Biosand Filter Production Group http://groups.google.com/group/bsf-production?hl=en Sand Sorter Update –April 2011 www.cawst.org

2. Outline: Purpose and Objectives How the process works Design of Sand Sorter – History & Progress Ron Ryde’s ‘Original’ ‘Alpha’ - 2nd design ‘Beta’ – 3rd design The ‘Zambia’ Sand Sorter The ‘India’ Sand Sorter What we learned in Zambia & India Positives Problems Solutions Next Steps and Future Plans Sand Sorter Update –April 2011 www.cawst.org

3. Purpose and Objectives Purpose of the Sand Sorter: To support the growth of biosand filter (bsf) production in the world; a machine is needed that can prepare the filtration sand and achieve higher quality and greater quantities than manual sieving and hand washing. Objectives: • A ‘fit-for-purpose’ machine design to prepare sand & gravel that meet the specifications for biosand filters. • Capable of being fabricated, operated and repaired in developing countries. • Open-content; free dissemination and cooperative improvements shared among bsf producers. Sand Sorter Update –April 2011 www.cawst.org

4. How the process works • Sand and gravel, saturated in water, is passed over 3 vibrating screens to sort and wash the sand into the specific sizes required for the biosand filters. • Changing the selection of the 3 screens provides the sizes needed for the filtration sand, separating layer and underdrain layer. • Water is used in the process to wash the very fine material off the sand and gravel. In this way the sand sorter both sieves and washes the sand & gravel in one operation. Sand Sorter Update –April 2011 www.cawst.org

5. Design of Sand Sorter - History Ron Ryde’s ‘Original’ First design; Designed and manufactured by Ron Ryde in N. America and transported via suitcase into Haiti and Zambia. Ron Ryde’s original design provided the basis and the stimulus for a design that could be built in-country…a task that CAWST undertook in 2009. Sand Sorter Update –April 2011 www.cawst.org

6. Ron Ryde’s Original Design Operating in Haiti… and in Zambia Sand Sorter Update –April 2011 www.cawst.org

7. Design of Sand Sorter - History Objectives for ‘Alpha’ -2nd design; Develop a prototype Sand Sorter that is sufficiently flexible to modify the important parameters to further progress the design. Fabricate a transportable model that can be used and demonstrated in various locations (in Canada). Generate drawings for fabrication. Conduct trial testing to determine quality of products, throughput capability, and ease of use and maintenance. Sand Sorter Update –April 2011 www.cawst.org

8. Design of Sand Sorter - History Objectives for ‘Beta’ – 3rd design; Design an affordable, effective and workable Sand Sorter that can be fabricated in the developing country where it will be used. Develop the drawings, photos and instructions for fabrication for the local skills and materials that can be located in developing countries. Produce a prototype that can be trial tested for quality of products, throughput capability, and ease of use and maintenance. Sand Sorter Update –April 2011 www.cawst.org

9. The ‘Zambia’Sand Sorter October 2010 Changes include: Revised design for available steel sizes More weight (of steel) meant frame needed reinforcement 1725 rpm motor was not available; needed different pulley sizes to reduce down to 915 rpm The first sand sorter of this design fabricated ‘in-country’ Kirk Schauer, Director, Seeds of Hope International Partnerships Sand Sorter Update –April 2011 www.cawst.org

10. The‘India’ Sand SorterMarch 2011 The biosand filtration sand will be prepared in Ranchi, Jharkhand and trucked to other biosand filter projects such as Kolkata, West Bengal. All the components could be found in NE India, however the larger the city the easier it was to find the correct steel dimensions and mechanical components Dhayang Norbu, Manager Biosand Filter Program Lalita, Coordinator Community Health Promotion Sand Sorter Update –April 2011 www.cawst.org

11. The‘India’ Sand SorterMarch 2011 Full operation requires additional equipment: Stationary feed hopper Stationary discharge chute Platform for operator Space was allowed for two more ‘in-line’ sand sorter machines Sand Sorter Update –April 2011 www.cawst.org

12. What we learned in Zambia & India • The sand sorter can be successfully built ‘in-country‘ • Cost is roughly $US 2000; about $1200 for machine plus $U800 for the stationary feed hopper & discharge chute and platforms • Equipment and tools needed: • Arc welder, drill press, metal chop saw, hand drill, hand grinder, vise, clamps, right angle square, wrenches, steel punch, caliper, hammer • Sourcing of most components was possible in Zambia; all components could be sourced in India. • Obtaining steel of the correct dimension, especially flat bar & angle iron, is important since the design is based on these sizes. • The frame needs to be well braced and the base of the frame needs to be cast in concrete. Sand Sorter Update –April 2011 www.cawst.org

13. What we learned in Zambia & India • A water recycle system using multiple settling tanks, with a submersible pump in the last tank, allows the wash water to be reused continually • The undersize material is most easily handled by allowing it to drop down onto the floor below rather than a discharge chute • A sloped floor below the sand sorter and running to the first water recycle tank makes it easier for the larger particles (of the ‘undersize’ material) to be removed from the water. • The hook edge on the screens can be made using galvanized sheet metal or by sandwiching the screen between flat bars. • The water spray system is not really needed and removing it provides much better access to the top screen. Hand-held hoses are preferred by the operators. Sand Sorter Update –April 2011 www.cawst.org

14. What we learned in Zambia & India Positives: • The vibration motion was very effective and consistent – the eccentric orbital motion never dampens. • The screens could be changed easily and quickly for cleaning (hook edge screens, tension rail and wedge system) • Sand sieve analysis showed that filtration sand could be produced within the specifications recommended by CAWST • Production capacity was good. Quote from Kirk at SHIP: “Although I still don't know the upper limit because of one thing or another …with a smaller crew we are still able to see the production numbers grow a lot…” Sand Sorter Update –April 2011 www.cawst.org

15. What we learned in Zambia & India Problems: • The flange bearings were difficult to align correctly; the two eccentric sleeves must be in line with one another to get the correct motion. • The flange bearings moved along the shaft during the initial days of operation in Zambia and had to be tightened 3 different times. • After about one week of operation the 0.6 mm galvanized sheet metal used for the discharge chutes failed along the hook edge where they are fastened to the vibrating frame. It was determined that the durability and longevity of this sheet metal is not adequate. Sand Sorter Update –April 2011 www.cawst.org

16. What we learned in Zambia & India Solutions: • For the sand sorter fabricated in India (March 2011) the flange bearings were aligned correctly and kept from moving by inserting a ‘set screw’ in the two eccentric sleeves to fasten them to the shaft. • The design of the discharge chutes was changed to 1.5 mm sheet metal welded to the vibrating screen housing and reinforced with angle iron. This material is now also used for the feed tray. Sand Sorter Update –April 2011 www.cawst.org

17. A set screw was placed in the India ‘Reiss Ryde’ Sand Sorter to prevent the bearings from moving out of place Eccentric flange bearings Sand Sorter Update –April 2011 www.cawst.org

18. Discharge chutes were welded onto the vibrating frame and reinforced with angle iron Zambia India Sand Sorter Update –April 2011 www.cawst.org

19. Sieve Screens The 3 screens and ‘catch pan’ are held in place with ‘tension rails’ designed to make it easy to remove and reinstall the screens. Screens are tensioned with wedges to transfer the vibration energy and to reduce screen wear. Hook edge on screen Sand Sorter Update –April 2011 www.cawst.org

20. Base of the frame should be cast in concrete. • A sloped floor leading to water recycle Sand Sorter Update –April 2011 www.cawst.org

21. Stationary feed hopper • Stationary discharge chute Sand Sorter Update –April 2011 www.cawst.org

22. Water recycle Submersible pump Product bag Sand Sorter Update –April 2011 www.cawst.org

23. Next Steps & Future Plans • Revise drawings for design changes from Africa and India experiences. • Release: CAWST Sand Sorter Version 1.0 • Generate instructions for fabrication including: • Steel order, cut list, materials legend and details of mechanical components for in-country fabrication • AutoCAD drawings, photos and notes for fabricator • Survey operators for learnings on Sand Sorter • Develop lessons-learned and best practices for bsf implementers using sand sorter machines Sand Sorter Update –April 2011 www.cawst.org